Devices, such as magnetic memory devices, may be formed using standard patterning techniques. Magnetic memory devices use magnetic memory cells to store information. Information is stored in such magnetic memory devices as the orientation of the magnetization of a storage layer in the magnetic memory cell as compared to the orientation of the magnetization of a reference layer in the memory cell. The magnetization of the storage layer may be oriented parallel or anti-parallel to the reference layer, representing either a logic “0” or a “1.” One type of memory cell, a magnetic tunnel junction (MTJ), comprises a storage layer and a reference layer separated by a tunnel barrier.
Patterning of the magnetic memory cells can be done with reactive ion etching, e.g., in a manner similar to that used to pattern transistors in complementary metal oxide semiconductor (CMOS) technology. Alternatively, patterning can be done with ion beam etching, e.g., in a manner similar to that used to pattern read heads for magnetic disk drives. During etching to pattern the magnetic memory cells, however, nonvolatile materials that have been removed from the wafer surfaces may become re-deposited on portions of the cell, having deleterious effects. The re-deposited materials can result in a poorly-defined cell shape, e.g., by terminating the edges with an ill-defined material. Further, in the case of an MTJ, for example, the re-deposited material can cause shorting across the tunnel barrier. Thus, use of conventional etching techniques can negatively affect the properties of the cell. This problem may be further worsened by the use of certain materials that are particularly difficult to etch, as they do not easily form volatile compounds when interacting with etch gasses at normal processing temperatures.
Therefore, etching techniques that minimize or eliminate the effects of re-deposited materials would be desirable.